merge the fix of SNOW-793: memory leak in LLImageFormatted::appendData

indra/llimage/llimage.cpp

@@ -1553,6 +1553,7 @@ void LLImageFormatted::appendData(U8 *data, S32 size)
 			S32 newsize = cursize + size;
 			reallocateData(newsize);
 			memcpy(getData() + cursize, data, size);
+			delete[] data;
 		}
 	}
 }